Circumference? Diameter is 2r. > -----Original Message----- > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On > Behalf Of Bob Bridges > Sent: Friday, June 18, 2021 10:30 AM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Re: Coding for the future > > Aha, my evil troll worked! BWA-HA-HA! > > Shmuel, I'm happy to take this off-line if you prefer, but I take the > definition of pi to be the ratio of the diameter of a circle to its radius. > In an uncurved space that ratio is constant; on the surface of a sphere, it > varies. If you insist on thinking in three dimensions -- three uncurved > dimensions -- then it will seem to you that the Flatlanders on that sphere > are simply mistaken about the radius about their circle. But I submit that > it's a mistake to dismiss their curved surface as an illusion, and to assume > our uncurved space is the only reality. > > I'm assuming you understand what I'm saying, and just disagree with me. > But > if you don't follow what I'm saying about the radius of a circle drawn on > the surface of a sphere, I'll bore you with further description. > > --- > Bob Bridges, robhbrid...@gmail.com, cell 336 382-7313 > > /* No single raindrop considers itself responsible for the flood. */ > > -----Original Message----- > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On > Behalf Of > Seymour J Metz > Sent: Friday, June 18, 2021 12:48 > > Sturgeon's Law. There is a lot of bad Mathematics and Bad Physics in Science > Fiction. pi is a true constant, not a physical variable, and curvature is > another animal entirely, whose definition doesn't even include a factor of > pi; it's defined entirely in terms of derivatives of the metric tensor, at > least in the cases relevant to current Physics. Bafflegab is always easier > than a correct explanation. > > If you're a flatlander living on a sphere pi doesn't change, but formulae > for, e.g., area, become more complicated. > > ________________________________________ > From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on > behalf of > Bob Bridges [robhbrid...@gmail.com] > Sent: Friday, June 18, 2021 12:34 PM > > Completely OT, I'm reminded of Greg Bear's _Eon_, in which someone > carried > around a device for measuring the local value of pi. It's a way of > detecting curvature in space, you see. You may think pi is 3.141519 > everywhere, but if you're a Flatlander living on the surface of a sphere > you'll have to get used to the fact that it can be anywhere between...let's > see...between 0 and 4, I think. > > -----Original Message----- > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On > Behalf Of > Seymour J Metz > Sent: Thursday, June 17, 2021 14:01 > > It may be tongue in cheek, but while the value of pi will never change, the > precision that you need may change, and changing a single precision 3.14159 > to a more precise extended precision value is a lot easier if it's only in > one place. > > Besides, while mathematical constants don't change, some physical > constants, > e.g., g, represent local conditions rather than laws of Physics. Take the > length of the day - please! > > ________________________________________ > From: Mark Jacobs [00000224d287a4b1-dmarc-requ...@listserv.ua.edu] > Sent: Thursday, June 17, 2021 11:49 AM > > The primary purpose of the DATA statement is to give names to constants; > instead of referring to pi as 3.141592653589793 at every appearance, the > variable PI can be given that value with a DATA statement and used instead > of the longer form of the constant. This also simplifies modifying the > program, should the value of pi change. > ― FORTRAN manual for Xerox Computers > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email > to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send email > to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
